Air flow control system

ABSTRACT

Environmental temperatures are controlled by selectively proportioning air flow from a pair of air flow paths by generation of a force proportional to temperature and dependent solely upon temperature for oppositely and proportionally changing registration of small openings in pairs of perforated plates laterally disposed in the air flow paths.

United States Patent Hall, Jr.

[ 1 June 13, 1972 [54] AIR FLOW CONTROL SYSTEM [72] Inventor: William K.Hall, Jr., 1221 Frito-Lay Tower, Dallas, Tex. 75235 [22] Filed: May 8,1967 [21] App1.No.: 636,748

Related [1.8. Application Data [63] Continuation-impart of Ser. No.577,298, Sept. 6,

1966, abandoned.

[52] us. c1. ..236/13, 98/38, 98/40 D, 165/16, 236/49 51 1111.01 ..G05d11/16, F.24r 13 04 [58] Field ot'Search ..98/38, 40, 38 E; 236/13, 49;165 22, 16

[56] References Cited UNITED STATES PATENTS 1,455,846 5 1923 Lewis..98/40 x 3,367,407 2/1968 Warren,.|r ..165/22 3,376,916 4/1968 Gressett..98/38 2,266,217 12/1941 Kings1and.. ..236/13 2,430,759 11/1947 Crise..236/13 X 2,835,449 5/1958 Joesting ..236/13 2,936,123 5/1960 Kreuttner.....236/13 2,971,450 2/1961 Millman ..98/38 3,114,505 12/1963Kennedy.... ...98/38 X 2,976,884 3/1961 Kurth et a1.. ..98/38 2,987,9826/1961 Wilson 1 ..98/38 3,179,338 4/1965 Ostrander ..98/38 PrimaryExaminer-William E. Wayner Attorney-Rogers, Ezell, Eilers & Robbins [57]ABSTRACT Environmental temperatures are controlled by selectivelyproportioning air flow from a pair of air flow paths by generation of aforce proportional to temperature and dependent solely upon temperaturefor oppositely and proportionally changing registration of smallopenings in pairs of perforated plates laterally disposed in the airflow paths.

10 Claims, 17 Drawing Figures PATENTEDJUN 13 I972 SHEET 2 OF 6 88 FIG. 3g

INVENTOR WILLIAM K. HALL, JR.

FIG. 4

ATTORNEY PATENTEDJUH13 I972 3, 669 349 sum 3 or e INVENTOR WILLIAM K.HALL, JR.

'Axww ATTORNEY PATENTEDJUH 1 3 I972 3 669 349 SHEET u 0F 6l'I'I'I'I'I'I'l Ir INVEN'TOR WILLIAM K. HALL, JR. A). QM M FIG. I3

ATTORNEY PATENTEDJUH 1 3 i972 SHEET 8 BF 6 INVENTOR WILLIAM K. HALL, JR.

ATTORNEY AIR FLOW CONTROL SYSTEM RELATED APPLICATIONS This applicationis a continuation-in-part of application Ser. No. 577,298, filed Sept.6, 1966, now abandoned.

FIELD OF THE INVENTION This invention relates to environmental controlsystems and more particularly to the control of air flow from warm andcool sources. In a more specific aspect, the invention relates to a flowcontrol system which includes pairs of relatively slidable perforatedplates positioned transversely of the flow paths leading from thesources. In a still further aspect, the invention relates to thedevelopment and direct use of forces produced solely in response tochange in temperature for varying relative positions of such perforatedplates.

PRIOR ART A wide variety of systems has been heretofore employed in thedelivery of air to one or more zones where individual con trol of thetemperature for each zone is desired. In the past, heat exchange unitshave been supplied for each zone with temperature sensing means forcontrolling the heat supplied to, or extracted from, air flowing to suchzone. In air flow systems, motor-driven mechanically-actuated dampershave been widely employed. Further, in high pressure systems, the flowof supercooled air under high pressure to a particular area has beenemployed for inducing circulation.

The practical utilization of many of these previously developedtemperature control systems has been limited by several factors. Many ofthe prior systems have not only required complex and expensive controland actuation devices for each temperature control unit, but have oftenrequired a separate control unit for each zone for which temperaturecontrol is desired. In addition to the economic limitations thus imposedupon many previously developed systems, the complex motor-operatedconstruction of some systems has often not been entirely satisfactorywith respect to maintenance requirements or operating efficiency.Further, many of the systems previously employed for zone temperaturecontrol have not been responsive to the temperature of air in thedesired zone.

SUMMARY In accordance with the present invention, conduit means ismounted adjacent to a supply opening leading to a zone to be temperaturecontrolled. Structure is provided which forms a -pair of air supplypaths which lead to the conduit means. A

THE DRAWINGS Other objects and intended advantages of this inventionwill be more readily appreciated as they become better understood byreference to the following detailed description in connection with theaccompanying drawings wherein:

FIG. 1 illustrates a system according to the present invention forindividually controlling the temperature in a plurality of adjacentrooms;

FIG. 2 illustrates a system for conditioning the temperature in aplurality of vertically disposed room zones;

FIG. 3 illustrates a system utilizing common returned air to temperaturecondition adjacently disposed room zones;

FIG. 4 is a perspective view, partially cut away, of one embodiment ofthe present invention;

FIG. 5 is a cross-sectional view of the sensing unit of the device shownin FIG. 4;

FIG. 6 is another perspective view of the device shown in FIG. 4;

FIG. 7 is a perspective sectional view of a portion of the perforatedplates shown in FIGS. 4 and 5;

FIG. 8 is a sectioned view of another embodiment of the perforatedplates of the present invention;

FIG. 9 is a cross-sectional view of another embodiment of the perforatedplates of the present invention;

FIG. 10 is a schematic diagram of a temperature conditioning systemutilizing the present invention;

FIG. 11 is a perspective sectional view of the system embodying thedevice shown in FIG. 4;

FIG. 12 is a somewhat schematic view, partially in cross section, of thesystem shown in FIG. 1 1;

FIG. 13 is a cross-sectional view of another embodiment of a sensingunit of the present invention;

FIGS. 14-17 are perspective views, partially. cut away, of fourdifferent temperature control systems utilizing perforated plate controlaccording to the present invention.

THE PREFERRED EMBODIMENTS FIGS. l-3 illustrate air temperature controlsystems wherein warm air or cool air reservoirs common to a plurality ofindividual zones to be temperature controlled may be utilized with theapplication of the present invention. FIG. 1 discloses a control systemwherein the temperature of air in several adjacently disposed rooms maybe maintained individually in accordance with their separaterequirements. A warm air reservoir or plenum 10, which may, for example,be an attic space fed by return air from rooms therebelow, is commonlydisposed to each of the rooms l2, l4, l6, and 18. Cool air is suppliedfrom a suitable source through a duct 20 which forms a cool air supplypath leading to a first control section 22 in a flow control unit 24constructed in accordance with the present invention. Warm air isreturned from the room 12 through the opening 26 to combined with thewarm air in the reservoir 10 to form a warm air supply path leading to asecond control section 28 on the control unit 24. The control sectionseach comprise pairs of perforated plates, one slidable with respect tothe other, and so actuated as to proportion the air flowing therethroughin dependence upon temperature, as will be described in greater detail.A fan is' located in the control unit 24 to pull air through the controlsections 22 and 28 in such proportions as required to control thetemperature of room 12. The air from the warm and the cool supply pathsis mixed and then supplied to room 12 through conduits 30 and 32 andthrough supply openings 34 and 36, respectively.

Also illustrated in FIG. 1 is another embodiment of a system utilizingthe present invention, wherein cool air from aduct 38 supplies a portionof air through openings 40 into room 14, opening 42 into room 16, andopening 44 into room 18 in such proportions as determined by the controlunits 46 and 48, constructed in accordance with the present invention.Warm air is. returned through opening 50 from room 14 into the reservoir10 for mixture with the cool air supplied by the duct 38 in suchproportions as is determined by the control unit 46. In a somewhatsimilar manner, warm air is supplied to an opening 52 from room 18 to bemixed with the cool air supplied by the duct 38 in such proportions asis determined by the control unit 48. The proportions of warm air andcool air are accurately controlled in response to sensing devicesexposed to air of the temperature of the air in the individual rooms,thus allowing individual temperature control of each of the adjacentlydisposed rooms. 7

FIG. 2 illustrates the use of the present invention in a temperaturecontrol system for a plurality of vertically disposed rooms in abuilding. A cool air reservoir or plenum 54, common to a plurality ofvertical rooms, contains cool air supplied by a blower 55 in aconventional cooling unit 56, which may utilize conventional dampers 58to control the inlet of outside air. A warm air return plenum 60contains warm exhaust air supplied by the rooms and from the cool airreservoir 54 through the grille 62. The plenum 60 is connected throughconduit 63 and suitable dampers to the cooling unit 56.

As may be seen, a system utilizing the present invention may take anyone of a variety of forms. For instance, the system for independentlycontrolling the temperature of room 64 supplies conditioned air to theinlets 66 through conduits 67, the conditioned air being mixed by thecontrol unit 68 from the warm air returned through the outlets 69 andthe cool air supplied through the path 70. A similar system is shown forconditioning the air of room 72 wherein rigid ductwork 74 is utilizedinstead of flexible conduits. If desired, a plurality of control unitsmay be utilized for conditioning a single room, as shown by the threeunits 76, 78, and 80, which selectively proportion the amount of coolair from the reservoir 54 and the warm air from the attic plenum 82mixed and provided to the room.

FIG. 3 illustrates a conditioning system for a pair of rooms 84 and 86which are commonly disposed to a warm air attic reservoir 88 and a coolair reservoir 90. Warm air from rooms 84 and 86 flows to a common plenum92 and a conduit 93 and thence into a conventional cooling system 94. Ablower unit 95 supplies a continuous supply of cool air to the reservoir90. Warm air also flows from the rooms 84 and 86 into the atticreservoir 88 through openings 85 and 87, respectively. A pair of controlunits 96 and 98, constructed in accordance with the present invention,are mounted between the warm air reservoir 88 and the cool air reservoir90 in order to selectively proportion the mixture of the two airsupplies which is fed into rooms 84 and 86, respectively.

While refrigeration units have been illustrated in conjunction with theembodiments described, it will be appreciated that, if desired, cold aircould be provided from an outside environment and heating means could beprovided to supply a source of warm air.

The construction of a control unit in accordance with the presentinvention may be best understood by reference to FIGS. 46, wherein theunit 100 is enclosed by a main housing 102. Housing 102 is an elongatedrectangular polyhedron conveniently formed of sheet metal. Housing 102may have one or more removable panels 104 for repair or maintenanceaccess.

A pair of conventional blower fan units 106 and 108 include rotatablevaned cages 109 and 1 l driven by an electric motor 111. The operationof electric motor 111 is controlled by a suitably placed wall switch 112connected through cable 113 which controls the application of power froma suitable source (not shown) to the motor. Rotation of the cages 109and 110 induces flow of supply air through a first perforated plate unit1 l4 and a second perforated plate unit 116.

Perforated plate units 114 and l 16, as shown in FIG. 6, are disposedrelative to one another at an angle corresponding with the junction ofwarm and cool air supply paths. Rectangular flanges 117 and 118 may beprovided about the outer openings of the plate sections in order toenable connection with air conduits. As shown in FIG. 7-, plate unit 114comprises a fixed plate 122 adjacent to a slidable plate 128. Plates 122and 128 have perforations therein which may be brought into registrationor moved out of registration to open or close the air flow path and thusproportion the air passing through the housing 102. Plate unit 1 16includes slidable plate 139 and fixed plate 134. Air flowing throughplate units 114 and 1 16 is expelled by the fan units through theirrespective outlets 119 and 120.

Referring again to FIG. 7, plate unit 114 comprises a first plate 122which is fixedly connected at one edge to a bracket member 124 which isin turn connected to the main housing 102 of the unit. The other edge ofthe plate 122 is connected to housing 102 by means of a folded flange125 (FIG. 4). Plate 122 includes a plurality of elongated perforations126 defined therethrough in a predetermined alternating pattern. Asecond plate 128, comprising one-half of an integral plate having acentral right angle bend, is slidable adjacent to the plate section 122.Plate 128 is connected to the rod 130, as by welding, for slide movementrelative to plate 122.

Plate 128 includes a plurality of elongated perforations 132 disposed inthe same pattern as the perforations 126 in the plate 122, so that theperforations in the adjoining plates may be selectively brought intoregistration or moved out of registration in order control the flow ofair therethrough. In FIG. 7, the perforations 126 and 132 are disposedin exact registration so that the passage of air therethrough issubstantially unimpeded. Upon a slight vertical movement of the rod 130,the perforations may be moved out of registration in order to accuratelyadjust the magnitude of the air flow therethrough.

The second plate unit 116 comprises a first plate 134 rigidly secured tothe bracket member 136 and having a plurality of elongated perforations138 disposed therethrough in a predetermined pattern. The plate 134 isoffset with respect to the plate 122 so that the perforations throughthe two plates are not aligned. The second half of the bent plate, plate139, has a plurality of perforations 140 and is adjacent to the plate134. Because the perforation patterns of plates 122 and 134 are offset,when the perforations of the plate unit 1 14 are exactly aligned, theperforations of the second plate unit 116 are unaligned. In such case,the flow of air through the second plate unit 1 16 is thus totallyobstructed.

Upon movement of the rod 130, however, the plates I28 and 139 would bemoved relative to both the plates 122 and 134, thereby decreasing theproportion of air allowed to pass through the first plate unit 1 14,while concurrently increasing the proportion of air allowed to passthrough the second plate unit 116. It will be understood that finecontrol of the passage of air, and similar control of mixing of air fromtwo different air supply paths, may be accomplished by the presentdevice. Only a very small mechanical movement is required to change onepair of plates from open to closed. The elongated slot configurationshown in FIG. 7 has the distinct advantage of not requiring extremelyaccurate manufacturing dimensioning to provide substantial registrationof the perforations while maintaining at a minimum the travel necessaryto open and close a pair of plates.

FIG. 5 discloses means for moving rod 130 to adjust the positions of theperforated plates. A fluid filler sensor 141 is connected in fluidcommunication with a fluid chamber 142 by means of a line 144. An insert146 within the chamber 142 limits the upward movement of the end 148 ofan elongated linkage 150. A housing 152 provides a fluid-tight sealabout the linkage 150, and a bias spring 154 is disposed between the end148 and the housing 152. A threaded portion 158 on the linkage providesfor connection to an extension 156 on the rod 130 in order to allowinitial adjustment of the position of the rod 130 for proper alignmentof the perforations.

A fluid conduit 160 connects the chamber 142 in fluid communication withan adjustment mechanism 162 comprising a hollow chamber 164 also filledwith the fluid. A slidable piston 166 is biased against the fluid in thechamber 164 by a spring 168. A dial 170 may be manually turned toselectively increase or decrease the tension applied by the piston 166against the fluid. The variance of pressure on the fluid acts on the end148 to move the linkage 150 vertically. By suitable adjustment of dial170, therefore, the static position of the rod 130 and the outer platesections 128 and 139 may be adjusted to provide either warmer or coolerair flow. I

In operation of the present unit, the dial 170 is set to the desiredoperating temperature. The sensor 141 senses air of the temperature ofair in a room. If the temperature increases, the fluid inside the sensor14] tends to expand, overcoming the bias pressure of the spring 154 andmoving the linkage 150 downwardly. This causes the'rod 130 and thus theperforated plate sections 128 and 139 to be moved downwardly, therebychanging the registration of the perforations. This movementconcurrently increases the amount of cool air and decreases the amountof warm air supplied to the room.

Conversely, if the temperature of the room air drops, the volume of thefluid inside the sensor 141 and the chamber 142 will decrease. Spring154 moves the perforated sections 128 and 139 upward. The change causesthe temperature of the air in the room to be raised. The novelconstruction of the present invention thus allows very accurate controlof the air supply to a room in response to only a very slight mechanicalmovement. This movement is within the capabilities of the expandablefluid sensing device 141.

Other configurations of perforations may be employed in the perforatedplates. For example, FIG. 8 illustrates a plurality of substantiallycircular perforations 171 distributed in predetermined patterns throughfixed plates 172 and 173. A movable outer plate 174 is connected, as bywelding, to the rod 176 for movement relative to the fixed plates 172and 173. The plate 174 includes a plurality of circular perforations 175which may be moved into registration with the openings of only one ofthe fixed plates 172 or 173 at a time.

FIG. 8 illustrates a position of the plate 174 such that theperforations 175 are in registration with the perforations in plate 172.In this position, the perforations in plate 174 are out of registrationwith the openings of the plate 173, thereby preventing the passage ofair therethrough. It will be understood that other configurations ofperforations may also be employed for the plates, as, for example,square, rectangular, and the like.

The plates above described may advantageously be constructed of rigidmaterial, preferably of stainless steel. Plate sections of other metals,such as aluminum or the like, may also be used when corrosion will notadversely affect operatron.

It may be found advantageous to construct one or more of the plates froma flexible material, in the manner illustrated in FIG. 9. In thisembodiment, the perforated plate 178 is constructed from stainlesssteel, while the perforated plate 180 is constructed from a flexiblematerial, such as neoprenecovered canvas or the like. By placing theflexible plate upstream of the rigid plate section, the pressure of theair flow against the flexible plate will press it against the rigidplate, thereby minimizing the loss of air through the space between theplates. Alternatively, a felt-like material may be bonded to one side oftwo stainless steel plates of a pair, and between them, in order to cutdown air loss and to resist corrosion.

FIG. illustrates another embodiment of a sensing apparatus for use withthe present control unit 181 above described for control of thetemperature in room 184. A bimetallic circuit controller 185 is mountedon the wall 187 or in some other suitable place in order to sense thetemperature of air in room 184. Such a bimetallic controllerconventionally changes from one position to another in order to open orclose an electrical contact (not shown). The controller 185 serves toenergize and de-energize a servo motor 186 which is connected through amechanical linkage 188 to the movable perforated plate sections 182 and183. Energization of the servo motor 186, also of a conventionalconstruction, selectively varies the alignment of the perforations inthe plate sections in order to control the content of the air beingsupplied to room 184.

FIGS. 11 and 12 illustrate a system utilizing the sensing device shownin FIG. 5. In this application, the control unit 190 has perforatedplate sections 191 and 192 operated in dependence upon an expandablefluid sensor 193. Sensor 193 is disposed in an air conduit 194. Theconduit 194 is connected at one end to a wall panel box 196 having aperforated front panel 198 to allow the passage of air from a roomtherethrough. The other end of the air conduit 194 is connected to ajunction box 200 mounted on the unit 190. Electric power from a suitablesource may be provided to energize the blower fans in the unit 190through cables 204 and 206.

An electrical switch 208 is remotely disposed from the unit 190 and ismounted on the perforated panel 198 in order to allow remote adjustmentof the speed of the blower in unit 190. Similarly, a temperatureselector mechanism 210, similar to that shown in FIG. 5, in fluidcommunication with the expandable liquid sensor 193, is mounted on theperforated panel 198 in order to allow remote adjustment of thetemperature of the air of the room.

The wall panel box 196 ordinarily will be mounted in the space betweenroom wall panels 212 and 214. The end of the air conduit 194 connectedto the junction box 200 is disposed upstream of the blower of the unitso that room air passes through the conduit 194 and flows over thesensor 193. If desired, the remote end of the conduit 194 may bedisposed between the wall panels 212 and 214 in order to sample warm airfrom the room being returned to a warm air reservoir. Alternatively, thesensor 193 may be disposed in a region downstream from the blower fansof the unit 190 in order to sample the air flow to a given room.

FIG. 13 illustrates another embodiment of a suitable temperature sensorfor mechanically moving perforated plates relative to one another. Ahousing 216 includes an inlet port 218 for entry of air whosetemperature is to be sampled and further includes an annular ring 221having outlet ports 220 for exhausting air.

A temperature sensitive device 222 contains an expandable material andmay be of the type manufactured by American- Standard Controls Division,Detroit, Michigan, and sold under the name Vernatherm Valve. Unit 222 ismounted on a bracket 224. A piston 226 is movable into and out of unit222 in response to expansion of the material therein in response totemperature changes. A pin 228 is connected to the piston 226 andincludes a threaded portion 230 adapted to connect to a rod 232. Rod 232is to be connected to the movable perforated plates above described. Asleeve 234 abuts a cup 236 which is biased by a spring 238. A base cup240 abuts the lower end of spring 238 and has a central opening throughwhich pin 228 passes.

The base cup 240 includes a threaded section 242 which threadedly mateswith threads in the annular ring 221. Ring 221 also includes a threadedportion 244 which mates with threads in the housing 216. The threadedportions 242 and 244 may be provided with threads of different pitch toallow for initial adjustment of the static position of the sensingdevice. A coarse adjustment may be made by rotation of the annular ring221. A fine adjustment may be made by rotation of the base member 240relative to the ring 221.

The sensor illustrated in FIG. 13 preferably is mounted on or near acontrol unit and is mechanically linked to movable perforated platesthrough the rod 232. The unit of FIG. 13 may be mounted in the conduitopening into a room in order to sense the temperature of the air beingsupplied to the room. Alternatively, it may be mounted in or near thereturn paths from a room. In each of these embodiments, a mechanicallinkage may connect the cup 240 to a manually operable wallmountedactuator or control knob to allow adjustment of the set point.

Other applications of the present invention will be apparent uponconsideration of FIGS. 14-17, wherein perforated plate control accordingto the present invention is utilized in four different types oftemperature control systems. FIG. 14 illustrates a supply grille orconduit 246 which has a rectangular frame 248 adapted to be releasablymounted in a supply opening leading to a room. A warm air supply path250 is partially defined by a duct collar 252 having insulation 254installed therein. A cool air supply path 256 is located beneath thewarm air supply path 250 and is defined by the collar 252and aninsulated divider partition 258.

The two air supply paths 250 and 256 are fed into the room from suitablesources through pairs of perforated plates constructed in accordancewith the present invention. More particularly, an integral perforatedplate 260 is rigidly mounted between the frame 248 and a bracket 262connected to the duct collar 252. A pair of movable perforated plates264 and 266 are slidably disposed in a groove in the bracket 262 and areconnected to the horizontally movable bar 268. Thus, a first pair ofperforated plates comprising the upper portion of plate 260 and themovable plate 264 is transversely disposed in the warm air path 250.Similarly, a second pair of perforated plates comprising the lowerportion of the fixed perforated plate 260 and the movable plate 266 istransversely disposed in the cool air supply path. The plate sectionpairs may thus be relatively moved, in the manner previously described,to selectively adjust the registration of the perforations in adjacentplates to control the mixture of warm and cool air which is supplied tothe room.

The force for moving bar 268 is provided by the power unit 270, whichmay, for instance, be of the expandable fluid or material typepreviously described. Pressure resulting from fluid expansion in thepower unit 270 acts upon the head 272 of a rod 274. A spring 276 biasesthe head 272 against the bottom of the lower housing 278 of the powerunit. The lower end of rod 274 is connected to a threaded member 280 byadjusting nut 282 in order to allow initial adjustment of the positionof the perforated plates. The threaded member 280 is connected to aprojection 284 from bar 268 by a plurality of screws 286. The frame 248and the fixed perforated plate 260 are thus made to be easily removedfor maintenance purposes. More particularly, screws 286 are disposed tobe easily accessible upon the removal of frame 248 and plate 260 toallow the movable plates 264 and 266 to be removed for servicing.

FIG. illustrates the use of perforated plates in a temperature controlsystem wherein cool air is forced into a room through a nozzle 288 and aduct 290. Return air from a warm air plenum may be selectively mixedwith the cool air by means of a venturi type action created by the flowof air through the nozzle 288. This venturi action induces flow of warmair into the duct 290 through the perforated plate pairs 292 and 294.

The perforated plate pairs include a horizontally slidable plate 296which is transversely disposed across both of the warm return air pathsand also across the cool air supply path. Plate 296 is connected to aguide bracket 298 which is horizontally slidably mounted upon a framemember 300 which rigidly connects nozzle 288 to the front duct frame301. A power unit 302 is connected to move the rod 304, which in turnmoves a projecting member 306 and bar 298.

A perforated plate 308 is mounted in the duct 290 adjacent to themovable perforated plate 296. The fixed perforated plate 308 maycomprise a unitary plate having a predetermined pattern of alignedperforations at the top and the bottom portions of the plate which aredisposed adjacent the movable plates 292 and 294, and a pattern ofhorizontally offset perforations in the middle portion of the platewhich is disposed transversely across the opening of the nozzle 288.

Alternatively, the movable plate 296 may comprise three sheets mountedadjacent to each other, with the perforations of the top and bottomplate sections being aligned and the perforations of the middle platebeing horizontally offset. In either embodiment, it will now be apparentthat when the movable perforated plate 296 is horizontally translated inresponse to changes of air temperature in the room to be conditioned,the proportion of cool air supplied through the duct 290 may beselectively modulated in one sense while the proportion of warm returnair is concurrently modulated in the opposite sense.

FIG. 16 illustrates another type of temperature control system 310,generally known as a double duct constant volume system. Warm air undera high pressure is fed through the supply inlet 312 into the housing314, while cool air under high pressure is supplied through the inlet316. A partition 318 divides the air supply paths inside the frontportion of the housing 314. The warm and the cool air are then mixed inthe back portions of the housing 314 in proportions determined bytransversely disposed perforated plates 320 and 322. The plate 322 isrigidly connected to the housing 314. Plate 320 is movable in responseto movements of the temperature sensitive power unit 324. The power unit324 moves the movable plate 320 by means of a projection 326 mounted ona transversely disposed bar 328 rigidly connected to plate 320. The bar328 is slidable through a slot 330 in the partition 318.

The perforated plates are supported by a spacer member 332 which hasprovisions to allow a sliding movement of the plate 320. Theperforations in the movable plate disposed in the warm air supply pathare horizontally offset with respect to the perforations in the movableplate disposed in the cool air supply path. This allows the proportionof air supplied to the room by the warm air supply path to beselectively increased while concurrently the proportion of air suppliedto the room by the cool air supply path is decreased, or vice versa.

FIG. 17 illustrates the use of the present invention in a temperaturecontrol system commonly termed a high velocity induction unit. In thissystem, a bypass control simultaneously modulates the amount of returnroom air which passes over heating or cooling coils and theamount ofreturn room air bypassed around the coils. For example, in theillustrated system of FIG. 17, return room air is induced to flowthrough a grille 333 and then through perforated plate units 334 and336. Air flow through plates 334 bypasses the heating or cooling coilsin zone 337. A bafile 338 separates the two flows of air. Air passingthrough plates 336 contacts the heat exchange elements in zone 337. Theperforated plate pairs are constructed in a manner similar to the unitspreviously described, with a slidable plate 340 being connected to abracket 342 which is horizontally moved by a power unit 343. The bracket342 slides along an edge portion of the baffle 338. A fixed plate 344 isconnected to the frame 346.

It will be understood from the embodiments previously described that theperforations of one perforated plate section in each of the perforatedplate pairs 334 and 336 are horizontally offset with respect to oneanother so that the proportion of room air return supplied through onepath may be concurrently increased while the proportion of room airreturn supplied through the second path is concurrently decreased.

Whereas the present specification has been described in considerabledetail with respect to several embodiments, it is to be understood thatthis description is merely for purposes of illustration and that changesor variations in the described embodiments may be made by personsskilled in the art without departing from the scope of the invention asdefined in the appended claims.

What is claimed is:

1. In a system for control of air in a room having a supply openingleading thereto, the combination which comprises:

a. a powered mixing box adapted to be mounted adjacent to said supplyopening for directing air through said supply opening into said room;

b. said powered mixing box having a first inlet opening, a

second inlet opening, and an outlet opening,

c. a first structure forming a warm air supply path leading to saidfirst inlet opening of said powered mixing box;

d. a second structure forming a cool air supply path leading to saidsecond inlet opening of said powered mixing box;

e. a first pair of plates, at least one of which is perforated;

f. said first pair of plates being mounted so they are alwaysimmediately adjacent said first inlet opening and are transverselydisposed in, and substantially normal to, said warm air supply path;

g. a second pair of plates, at least one of which is perforated;

h. said second pair of plates being mounted so they are alwaysimmediately adjacent said second inlet opening and are transverselydisposed in, and substantially normal to, said cool air supply path;

i. means interconnecting one plate of each pair for moving one plate ofsaid first pair relative to the other in a first sense while moving oneplate of said second pair relative to the other in a second sense toincrease the proportion of air supplied to said powered mixing boxthrough one air supply path while concurrently decreasing the proportionof air supplied to said powered mixing box through the other air supplypath;

j. said outlet opening being located in one wall of said powered mixingbox and both of said inlet openings being displaced short distances fromsaid one wall of said powered mixing box to define a space which iswholly within said powered mixing box and which is bounded by saidoutlet opening and by said pairs of perforated plates, and

k. a fan that is mounted in said space within said powered mixing boxand that is immediately adjacent to said pairs of plates;

1. said fan being disposed within said space within said powered mixingbox but being located downstream from said plates of said first pair ofplates and also being located downstream from said plates of said secondpair of plates,

m. said fan receiving warm air from said warm air supply path via saidfirst inlet opening and said first pair of plates and receiving cool airfrom said cool air supply path via said second inlet opening and saidsecond pair of plates and mixing said warm air and cool air and thenmoving said mixed air through said outlet opening and into said roomthrough said supply opening.

2. The combination set forth in claim 1 wherein said first inlet openingis located in a second wall of said powered mixing box, wherein saidsecond inlet opening is located in a third wall of said powered mixingbox, wherein said second and said third walls abut each other to subtendan angle of substantially ninety degrees, whereby said pairs of platesare disposed relative one to another at an angle of substantially ninetydegrees, and wherein three sides of said space within said poweredmixing box are defined and delimited by said one and said second andsaid third walls of said powered mixing box.

3. A system for controlling the temperatures within a plurality of roomswhich comprises:

a. a plenum forming a cold air reservoir common to said plurality ofrooms, means including an air unit having the outlet thereof connectedto said plenum for supplying and creating flow of cold air into saidcold air reservoir,

c. a second plenum common to said plurality of rooms,

d. structure connecting each of said rooms with said second plenum topermit return air from said rooms to enter said second plenum,

said air unit having the inlet thereof connected to said second plenumto receive said return air from said rooms via said second plenum,

f. a plurality of separate air drive means opening into said rooms,

g. each of said air drive means having a first inlet for receiving warmair, a second inlet connected to the first said plenum for receivingcold air from said cold air reservoir, a fan, a proportioning damperbetween said inlets and said fan, and an outlet for mixed air,

h. said proportioning damper varying the proportions of warm air andcold air which said fan draws through said first and second inlets,respectively, and then discharges through said mixed air outlet,

'. the first said plenum being substantially larger in cross sectionthan the discharge outlet of said air unit, and being substantiallylarger in cross section than the second inlet of any of said separateair drive means, whereby the first said plenum holds a large volume ofcold air im mediately available to said separate air drive means,

j. said second plenum being substantially larger in cross section thansaid inlet of said air unit, whereby said second plenum holds a largevolume of return air immediately available to said air unit, and

k. means responsive to the temperature of air in a given room forcontrol of the position of said proportioning damper, in said air drivemeans for said room, to determine the relative proportions of warm andcold air introduced into said room by its air drive means.

4. A system for controlling the temperatures within a plurality of roomswhich comprises:

a. a plenum forming a cold air reservoir common to said plurality ofrooms,

b. means including an air unit having the outlet thereof connected tosaid plenum for supplying and creating flow of cold air into said coldair reservoir,

c. a second plenum common to said plurality of rooms,

d. structure connecting each of said rooms with said second plenum topermit return air from said rooms to enter said second plenum,

e. said air unit having the inlet thereof connected to said secondplenum to receive said return air from said rooms via said secondplenum,

. a plurality of separate air drive means opening into said rooms,

g. each of said air drive means having a first inlet for receiving warmair, a second inlet connected to the first said plenum for receivingcold air from said cold air reservoir, a fan, a proportioning damperbetween said inlets and said fan, and an outlet for mixed air,

h. said proportioning damper varying the proportions of warm air andcold air which said fan draws through said first and second inlets,respectively, and then discharges through said mixed air outlet,

. the first said plenum being substantially larger in cross section thanthe discharge outlet of said air unit, and

being substantially larger in cross section than the second inlet of anyof said separate air drive means, whereby the first said plenum holds alarge volume of cold air immediately available to said separate airdrive means,

j. said second plenum being substantially larger in cross section thansaid inlet of said air unit, whereby said second plenum holds a largevolume of return air immediately available to said air unit,

k. means responsive to the temperature of air in a given room forcontrol of the position of said proportioning damper, in said air drivemeans for said room, to determine the relative proportions of warm andcool air introduced into said room by its air drive means,

. the first said plenum and said second plenum being horizontallydirected,

in. one of said plenums being located immediately above the other ofsaid plenums,

n. the lower limit of said one plenum and the upper limit of said otherplenum being defined and delimited by a horizontally-directed partitionmeans,

0. the return air flow through said second plenum being in one directionrelative to said rooms, and

p. the cold air flow through said one plenum being in the oppositedirection relative to said rooms.

5. A system for controlling the temperatures within a plurality of roomswhich comprises:

a. a plenum forming a cold air reservoir common to said plurality ofrooms, I

means including an air unit having the outlet thereof connected to saidplenum for supplying and creating flow of cold air into said cold airreservoir,

. a second plenum common to said plurality of rooms,

structure connecting each of said rooms with said second plenum topermit return air from said rooms to enter said second plenum,

e. said air unit having the inlet thereof connected to said secondplenum to receive said return air from said rooms via said secondplenum,

a plurality of separate air drive means opening into said rooms,

g. each of said air drive means having a first inlet for receiving warmair, a second inlet connected to the first said plenum for receivingcold air from said cold air reservoir, a fan, a proportioning damperbetween said inlets and said fan, and an outlet for mixed air,

h. said proportioning damper varying the proportions of warm air andcold air which said fan draws through said first and second inlets,respectively, and then discharges through said mixed air outlet,

i. the first said plenum being substantially larger in cross sectionthan the discharge outlet of said air unit, and being substantiallylarger in cross section than the second inlet of any of said separateair drive means, whereby the first said plenum holds a large volume ofcold air immediately available to said separate air drive means,

said second plenum being substantially larger in cross section than saidinlet of said air unit, whereby said second plenum holds a large volumeof return air immediately available to said air unit,

. means responsive to the temperature of air in a given in. connectingmeans for permitting warm air flow from said warm air reservoir intosaid first inlets of said air drive means through said connecting means.

An atmosphere control system for a building having a plurality of roomswhich comprises:

a cooling unit that includes a blower which can supply quantities ofcooled air,

structural elements of said building which define and delimit parts ofrooms of said building and which also define and delimit part of a largecross section plenum that extends from a point adjacent said coolingunit to the immediate proximity of said rooms,

. the outlet of said blower of said cooling unit being connected to saidplenum for feeding cool air into said plenum from said cooling unit, andsaid plenum conducting said cool air to the immediate proximity of saidrooms,

a plurality of air-mixing boxes,

said air-mixing boxes being disposed adjacent said rooms,v

and each of said air-mixing boxes having structure forming two inletports, a fan mounted between said inlet ports and a discharge portleading to a room,

said fan in said air-mixing box acting to move air from said inlet portsto and through said discharge port and thence into said room,

. a cool air flow path between said plenum and one'of said inlet portsof each said air-mixing box to conduct cool air from said plenum to saidone inlet port,

. further structural elements of said building which define and delimitparts of rooms of said building and which also define and delimit partof a second large cross section plenum that extends from the immediateproximity of said rooms to a point adjacent said cooling unit,

. the inlet of said blower of said cooling unit being connected to saidsecond plenum,

. a warm air flow path from each said room to a second of said inletports of said air-mixing boxfeeding said room to conduct air from saidroom to said second inlet port,

structure forming flow paths from said rooms to said second plenum toinclude return air from said rooms in the air flowing through saidsecond plenum,

. said second plenum conducting return air from said rooms to saidcooling unit and thereby enabling said cooling unit to cool return airfrom said rooms and to include the cooled return air in the air whichsaid cooling unit supplies to the first said plenum,

m. temperature responsive means in said rooms, and

proportioning damper means in each said air-mixing box between the inletports thereof and the fan therein to vary the relative amounts of cooledair entering each air-mixing box from the first said plenum and theamounts of air entering each air-mixing box from the room.

An atmosphere control system for a building having a plurality of roomswhich comprises:

a powered cooler for supplying quantities of cool air,

means which define and delimit an air-distributing passage that extendsfrom a point adjacent said powered cooler to the immediate proximity ofsaid rooms,

. the outlet of said powered cooler being connected to saidair-distributing passage for feeding cool air into said airdistributingpassage from said powered cooler, and said air-distributing passageconducting said cool air to the immediate proximity of said rooms,

. a plurality of air-mixing boxes,

said air-mixing boxes being disposed adjacent to said rooms and each ofsaid air-mixing boxes having structure fonning two inlet ports, a fanmounted between said inlet ports and a discharge port leading to a room,said fan in said air-mixing box acting to move air from said inlet portsto and through said discharge port and thence into said room,

a cool air flow path between said air-distributing passage and one ofsaid inlet ports of each said air-mixing box to conduct cool air fromsaid air-distributing passage to said one inlet port,

a warm air flow path from each said room to a second of said inlet portsof said air-mixing box feeding said room to conduct air from said roomto said second inlet port, structure forming a return flow path fromsaid rooms to the inlet of said powered cooler to enable said poweredcooler to receive and cool return air from said rooms and to incorporatethe cooled return air in the air which said powered cooler supplies tosaid air-distributing passage,

j. temperature responsive means in said rooms,

a proportioning damper in each said air-mixing box between the inletports thereof and the fan therein to vary the relative amounts of airentering each air-mixing box from said air-distributing passage and theamounts of air entering each air-mixing box from the room, and meansproviding a continuously-open path which extends from the outlet of saidpowered blower to the inlet of said powered blower,

in. said continuously-open path means conducting substantially all ofthe air, supplied by said powered blower, from said outlet of saidpowered blower to said inlet of said powered blower whenever all of saidproportioning dampers in all of said air-mixing boxes are closed and actto prevent air in said air-distributing passage from entering saidair-mixing boxes,.

. thereby preventing any build-up of pressure within saidair-distributing passage,

said continuously-open path means conducting progressively less of theair, supplied by said powered blower, from said outlet of said poweredblower to said inlet of said powered blower as said proportioningdampers in said air-mixing boxes respond, to said temperature responsivemeans in said rooms, to progressively permit air from saidair-distributing passage to enter said air-mixing boxes.

An atmosphere control system for a building having a plurality of roomswhich comprises:

a powered cooler for supplying quantities of cool air,

means which define and delimit an air-distributing passage that extendsfrom a point adjacent said powered cooler to the immediate proximity ofsaid rooms,

. the outlet of said powered cooler being connected to saidair-distributing passage for feeding cool air into said airdistributingpassage from said powered cooler, and said air-distributing passageconducting said cool air to the immediate proximity of said rooms,

. a plurality of powered air-mixing boxes,

said air-mixing boxes being disposed adjacent to said rooms and each ofsaid air-mixing boxes having structure forming two inlet ports, a fanmounted between said inlet ports and a discharge port leading to a room,

said fan in said air-mixing box acting to move air from said inlet portsto and through said discharge port and thence into said room,

a cool air flow path between said air-distributing passage and one ofsaid inlet ports of each said air-mixing box to conduct cool air fromsaid air-distributing passage to said one inlet port,

. a warm air flow path from each said room to a second of said inletports of said ainmixing box feeding said room to conduct air from saidroom to said second inlet port,

. structure forming a return flow path from said rooms to said poweredcooler to enable said powered cooler to cool return air from said roomsand to include the cooled return air in the air which said poweredcooler supplies to said airrdistributing passage,

j. temperature responsive means in said rooms,

k. a proportioning damper in each said air-mixing box between the inletports thereof and the fan therein to vary the relative amounts of airentering each air-mixing box from said air-distributing passage and theamounts of air entering each air-mixing box from the room,

I. continuously-open passages interconnecting said rooms with saidreturn air structure,

in. means providing a continuously-open path between saidair-distributing passage and said return air structure,

n. said continuously-open passages between said rooms and said returnair structure and said continuously-open path means coacting to connectsaid rooms with said air-distributing passage via said return airstructure,

. whereby said rooms are connected to said air-distributing passage bothby said air-mixing boxes and by said continuously-open path means andthe continuously-open passages which interconnect said air returnstructure with said rooms.

9. An atmosphere control system for a building having a plurality ofrooms which comprises:

a. a cooling unit that includes a blower which can supply quantities ofcooled air,

b. structural elements of said building which define and delimit partsof rooms of said building and which also define and delimit part of alarge cross section plenum that extends from a point adjacent saidcooling unit to the immediate proximity of said rooms, the outlet ofsaid blower of said cooling unit being connected to said plenum forfeeding cool air into said plenum from said cooling unit, and saidplenum conducting said cool air to the immediate proximity of saidrooms,

a plurality of air-mixing boxes, said air-mixing boxes being disposedadjacent said rooms,

and each of said air-mixing boxes having structure forming two inletports, a fan mounted between said inlet ports and a discharge portleading to a room,

said fan in said air-mixing box acting to move air from said inlet portsto and through said discharge port and thence into said room,

a cool air flow path between said plenum and one of said inlet ports ofeach said air-mixing box to conduct cool air from said plenum to saidone inlet port,

. further structural elements of said building which define and delimitparts of rooms of said building and which also define and delimit partof a second large cross section plenum that extends from the immediateproximity of said rooms to a point adjacent said cooling unit,

. the inlet of said blower of said cooling unit being connected to saidsecond plenum,

j. a warm air flow path from each said room to a second of said inletports of said air-mixing box feeding said room to conduct air from saidroom to said second inlet port,

k. structure forming flow paths from said rooms to said second plenum toinclude return air from said rooms in the air flowing through saidsecond plenum,

. said second plenum conducting return air from said rooms to saidcooling unit and thereby enabling said cooling unit to cool return airfrom said rooms and to include the cooled return air in the air whichsaid cooling unit supplies to the first said plenum,

m. temperature responsive means in said rooms,

n. proportioning damper means in each said air-mixing box between theinlet ports thereof and the fan thereinto vary the relative amounts ofcooled air entering each air-mixing box from the first said plenum andthe amounts of air entering each air-mixing box from the room,

0. the first said plenum and said second plenum beinghorizontally-directed,

p. one of said plenums being located immediately above the other of saidplenums, q. the lower limit of said one plenum and the upper limit ofsaid other plenum being defined and delimited by a horizontally-directedpartition means,

r. the return air fiow through said second one direction relative tosaid rooms, and

s. the cold air flow through said one plenum being in the oppositedirection relative to said rooms.

10. An atmosphere control system for a building having a plurality ofrooms which comprises:

a. a cooling unit that includes a blower which can quantities of cooledair,

b. structural elements of said building which define and delimit partsof rooms of said building and which also define and delimit part of alarge cross section plenum that extends from a point adjacent saidcooling unit to the immediate proximity of said rooms,

c. the outlet of said blower of said cooling unit being connected tosaid plenum for feeding cool air into said plenum from said coolingunit, and said plenum conducting said cool air to the immediateproximity of said rooms,

d. a plurality of air-mixing boxes,

e. said air-mixing boxes being disposed adjacent said rooms,

and each of said air-mixing boxes having structure forming two inletports, a fan mounted between said inlet ports and a discharge portleading to a room,

f. said fan in said air-mixing box acting to move air from said inletports to and through said discharge port and thence into said room,

g. a cool air flow path between said plenum and one of said inlet portsof each said air-mixing box to conduct cool air from said plenum to saidone inlet port,

h. further structural elements of said building which define and delimitparts of rooms of said building and which also define and delimit partof a second large cross section plenum that extends from the immediateproximity of said rooms to a point adjacent said cooling unit,

i. the inlet of said blower of said cooling unit being connected to saidsecond plenum,

j. a warm air flow path from each said room to a second of said inletports of said air-mixing box feeding said room to conduct air from saidroom to said second inlet port,

k. structure forming flow paths from said rooms to said second plenum toinclude return air from said rooms in the air flowing through saidsecond plenum,

. said second plenum conducting return air from said rooms to saidcooling unit and thereby enabling said cool-ing unit to cool return airfrom said rooms and to include the cooled return air in the air whichsaid cooling unit supplies to the first said plenum,

m. temperature responsive means in said rooms,

n. proportioning damper means in each said air-mixing box between theinlet ports thereof and the fan therein to vary the relative amounts ofcooled air entering each air-mixing box from the first said plenum andthe amounts of air entering each air-mixing box from the room,

0. the first said plenum being located between said rooms,

p. the first said structural elements being the upper portions ofconfronting walls of said rooms plus a horizontallydirected ceilingextending between said upper portions of said confronting walls, and

q. a lower ceiling defining the bottom of the first said plenum.

plenum being in pp y

1. In a system for control of air in a room having a supply openingleading thereto, the combination which comprises: a. a powered mixingbox adapted to be mounted adjacent to said supply opening for directingair through said supply opening into said room; b. said powered mixingbox having a first inlet opening, a second inlet opening, and an outletopening, c. a first structure forming a warm air supply path leading tosaid first inlet opening of said powered mixing box; d. a secondstructure forming a cool air supply path leading to said second inletopening of said powered mixing box; e. a first pair of plates, at leastone of which is perforated; f. said first pair of plates being mountedso they are always immediately adjacent said first inlet opening and aretransversely disposed in, and substantially normal to, said warm airsupply path; g. a second pair of plates, at least one of which isperforated; h. said second pair of plates being mounted so they arealways immediately adjacent said second inlet opening and aretransversely disposed in, and substantially normal to, said cool airsupply path; i. means interconnecting one plate of each pair for movingone plate of said first pair relative to the other in a first sensewhile moving one plate of said second pair relative to the other in asecond sense to increase the proportion of air supplied to said poweredmixing box through one air supply path while concurrently decreasing theproportion of air supplied to said powered mixing box through the otherair supply path; j. said outlet opening being located in one wall ofsaid powered mixing box and both of said inlet openings being displacedshort distances from said one wall of said powered mixing box to definea space which is wholly within said powered mixing box and which isbounded by said outlet opening and by said pairs of perforated plates,and k. a fan that is mounted in said space within said powered mixingbox and that is immediately adjacent to said pairs of plates; l. saidfan being disposed within said space within said powered mixing box butbeing located downstream from said plates of said first pair of platesand also being located downstream from said plates of said second pairof plates, m. said fan receiving warm air from said warm air supply pathvia said first inlet opening and said first pair of plates and receivingcool air from said cool air supply path via said second inlet openingand said second pair of plates and mixing said warm air and cool air andthen moving said mixed air through said outlet opening and into saidroom through said supply opening.
 2. The combination set forth in claim1 wherein said first inlet opening is located in a second wall of saidpowered mixing box, wherein said second inlet opening is located in athird wall of said powered mixing box, wherein said second and saidthird walls abut each other to subtend an angle of substantially ninetydegrees, whereby said pairs of plates are disposed relative one toanother at an angle of substantially ninety degrees, and wherein threesides of said space within said powered mixing box are defined anddelimited by said one and said second and said third walls of saidpowered mixing box.
 3. A system for controlling the temperatures withina plurality of rooms which comprises: a. a plenum forming a cold airreservoir common to said plurality of rooms, b. meanS including an airunit having the outlet thereof connected to said plenum for supplyingand creating flow of cold air into said cold air reservoir, c. a secondplenum common to said plurality of rooms, d. structure connecting eachof said rooms with said second plenum to permit return air from saidrooms to enter said second plenum, e. said air unit having the inletthereof connected to said second plenum to receive said return air fromsaid rooms via said second plenum, f. a plurality of separate air drivemeans opening into said rooms, g. each of said air drive means having afirst inlet for receiving warm air, a second inlet connected to thefirst said plenum for receiving cold air from said cold air reservoir, afan, a proportioning damper between said inlets and said fan, and anoutlet for mixed air, h. said proportioning damper varying theproportions of warm air and cold air which said fan draws through saidfirst and second inlets, respectively, and then discharges through saidmixed air outlet, i. the first said plenum being substantially larger incross section than the discharge outlet of said air unit, and beingsubstantially larger in cross section than the second inlet of any ofsaid separate air drive means, whereby the first said plenum holds alarge volume of cold air immediately available to said separate airdrive means, j. said second plenum being substantially larger in crosssection than said inlet of said air unit, whereby said second plenumholds a large volume of return air immediately available to said airunit, and k. means responsive to the temperature of air in a given roomfor control of the position of said proportioning damper, in said airdrive means for said room, to determine the relative proportions of warmand cold air introduced into said room by its air drive means.
 4. Asystem for controlling the temperatures within a plurality of roomswhich comprises: a. a plenum forming a cold air reservoir common to saidplurality of rooms, b. means including an air unit having the outletthereof connected to said plenum for supplying and creating flow of coldair into said cold air reservoir, c. a second plenum common to saidplurality of rooms, d. structure connecting each of said rooms with saidsecond plenum to permit return air from said rooms to enter said secondplenum, e. said air unit having the inlet thereof connected to saidsecond plenum to receive said return air from said rooms via said secondplenum, f. a plurality of separate air drive means opening into saidrooms, g. each of said air drive means having a first inlet forreceiving warm air, a second inlet connected to the first said plenumfor receiving cold air from said cold air reservoir, a fan, aproportioning damper between said inlets and said fan, and an outlet formixed air, h. said proportioning damper varying the proportions of warmair and cold air which said fan draws through said first and secondinlets, respectively, and then discharges through said mixed air outlet,i. the first said plenum being substantially larger in cross sectionthan the discharge outlet of said air unit, and being substantiallylarger in cross section than the second inlet of any of said separateair drive means, whereby the first said plenum holds a large volume ofcold air immediately available to said separate air drive means, j. saidsecond plenum being substantially larger in cross section than saidinlet of said air unit, whereby said second plenum holds a large volumeof return air immediately available to said air unit, k. meansresponsive to the temperature of air in a given room for control of theposition of said proportioning damper, in said air drive means for saidroom, to determine the relative proportions of warm and cool airintroduced into said room by its air drive means, l. the first saidplenum and said second plenum being horizontally directed, m. one ofsaid plenums being located immediately above the other of said plenums,n. the lower limit of said one plenum and the upper limit of said otherplenum being defined and delimited by a horizontally-directed partitionmeans, o. the return air flow through said second plenum being in onedirection relative to said rooms, and p. the cold air flow through saidone plenum being in the opposite direction relative to said rooms.
 5. Asystem for controlling the temperatures within a plurality of roomswhich comprises: a. a plenum forming a cold air reservoir common to saidplurality of rooms, b. means including an air unit having the outletthereof connected to said plenum for supplying and creating flow of coldair into said cold air reservoir, c. a second plenum common to saidplurality of rooms, d. structure connecting each of said rooms with saidsecond plenum to permit return air from said rooms to enter said secondplenum, e. said air unit having the inlet thereof connected to saidsecond plenum to receive said return air from said rooms via said secondplenum, f. a plurality of separate air drive means opening into saidrooms, g. each of said air drive means having a first inlet forreceiving warm air, a second inlet connected to the first said plenumfor receiving cold air from said cold air reservoir, a fan, aproportioning damper between said inlets and said fan, and an outlet formixed air, h. said proportioning damper varying the proportions of warmair and cold air which said fan draws through said first and secondinlets, respectively, and then discharges through said mixed air outlet,i. the first said plenum being substantially larger in cross sectionthan the discharge outlet of said air unit, and being substantiallylarger in cross section than the second inlet of any of said separateair drive means, whereby the first said plenum holds a large volume ofcold air immediately available to said separate air drive means, j. saidsecond plenum being substantially larger in cross section than saidinlet of said air unit, whereby said second plenum holds a large volumeof return air immediately available to said air unit, k. meansresponsive to the temperature of air in a given room for control of theposition of said proportioning damper, in said air drive means for saidroom, to determine the relative proportions of warm and cool airintroduced into said room by its air drive means, l. a warm airreservoir located above, but common to, said rooms, and m. connectingmeans for permitting warm air flow from said warm air reservoir intosaid first inlets of said air drive means through said connecting means.6. An atmosphere control system for a building having a plurality ofrooms which comprises: a. a cooling unit that includes a blower whichcan supply quantities of cooled air, b. structural elements of saidbuilding which define and delimit parts of rooms of said building andwhich also define and delimit part of a large cross section plenum thatextends from a point adjacent said cooling unit to the immediateproximity of said rooms, c. the outlet of said blower of said coolingunit being connected to said plenum for feeding cool air into saidplenum from said cooling unit, and said plenum conducting said cool airto the immediate proximity of said rooms, d. a plurality of air-mixingboxes, e. said air-mixing boxes being disposed adjacent said rooms, andeach of said air-mixing boxes having structure forming two inlet ports,a fan mounted between said inlet ports and a discharge port leading to aroom, f. said fan in said air-mixing box acting to move air from saidinlet ports to and through said discharge port and thence into saidroom, g. a cool air flow path between said plenum and one of said inletports of each said air-mixing box to conduct cool air from said plenumto said one inlet port, h. further structural elements of said buildingwHich define and delimit parts of rooms of said building and which alsodefine and delimit part of a second large cross section plenum thatextends from the immediate proximity of said rooms to a point adjacentsaid cooling unit, i. the inlet of said blower of said cooling unitbeing connected to said second plenum, j. a warm air flow path from eachsaid room to a second of said inlet ports of said air-mixing box feedingsaid room to conduct air from said room to said second inlet port, k.structure forming flow paths from said rooms to said second plenum toinclude return air from said rooms in the air flowing through saidsecond plenum, l. said second plenum conducting return air from saidrooms to said cooling unit and thereby enabling said cooling unit tocool return air from said rooms and to include the cooled return air inthe air which said cooling unit supplies to the first said plenum, m.temperature responsive means in said rooms, and n. proportioning dampermeans in each said air-mixing box between the inlet ports thereof andthe fan therein to vary the relative amounts of cooled air entering eachair-mixing box from the first said plenum and the amounts of airentering each air-mixing box from the room.
 7. An atmosphere controlsystem for a building having a plurality of rooms which comprises: a. apowered cooler for supplying quantities of cool air, b. means whichdefine and delimit an air-distributing passage that extends from a pointadjacent said powered cooler to the immediate proximity of said rooms,c. the outlet of said powered cooler being connected to saidair-distributing passage for feeding cool air into said air-distributingpassage from said powered cooler, and said air-distributing passageconducting said cool air to the immediate proximity of said rooms, d. aplurality of air-mixing boxes, e. said air-mixing boxes being disposedadjacent to said rooms and each of said air-mixing boxes havingstructure forming two inlet ports, a fan mounted between said inletports and a discharge port leading to a room, f. said fan in saidair-mixing box acting to move air from said inlet ports to and throughsaid discharge port and thence into said room, g. a cool air flow pathbetween said air-distributing passage and one of said inlet ports ofeach said air-mixing box to conduct cool air from said air-distributingpassage to said one inlet port, h. a warm air flow path from each saidroom to a second of said inlet ports of said air-mixing box feeding saidroom to conduct air from said room to said second inlet port, i.structure forming a return flow path from said rooms to the inlet ofsaid powered cooler to enable said powered cooler to receive and coolreturn air from said rooms and to incorporate the cooled return air inthe air which said powered cooler supplies to said air-distributingpassage, j. temperature responsive means in said rooms, k. aproportioning damper in each said air-mixing box between the inlet portsthereof and the fan therein to vary the relative amounts of air enteringeach air-mixing box from said air-distributing passage and the amountsof air entering each air-mixing box from the room, and l. meansproviding a continuously-open path which extends from the outlet of saidpowered blower to the inlet of said powered blower, m. saidcontinuously-open path means conducting substantially all of the air,supplied by said powered blower, from said outlet of said powered blowerto said inlet of said powered blower whenever all of said proportioningdampers in all of said air-mixing boxes are closed and act to preventair in said air-distributing passage from entering said air-mixingboxes, n. thereby preventing any build-up of pressure within saidair-distributing passage, o. said continuously-open path meansconducting progressively less of the air, supplied by said poweredblower, from said outlet of said powered blower to said inlet of saidpowered blower as said proportioning dampers in said air-mixing boxesrespond, to said temperature responsive means in said rooms, toprogressively permit air from said air-distributing passage to entersaid air-mixing boxes.
 8. An atmosphere control system for a buildinghaving a plurality of rooms which comprises: a. a powered cooler forsupplying quantities of cool air, b. means which define and delimit anair-distributing passage that extends from a point adjacent said poweredcooler to the immediate proximity of said rooms, c. the outlet of saidpowered cooler being connected to said air-distributing passage forfeeding cool air into said air-distributing passage from said poweredcooler, and said air-distributing passage conducting said cool air tothe immediate proximity of said rooms, d. a plurality of poweredair-mixing boxes, e. said air-mixing boxes being disposed adjacent tosaid rooms and each of said air-mixing boxes having structure formingtwo inlet ports, a fan mounted between said inlet ports and a dischargeport leading to a room, f. said fan in said air-mixing box acting tomove air from said inlet ports to and through said discharge port andthence into said room, g. a cool air flow path between saidair-distributing passage and one of said inlet ports of each saidair-mixing box to conduct cool air from said air-distributing passage tosaid one inlet port, h. a warm air flow path from each said room to asecond of said inlet ports of said air-mixing box feeding said room toconduct air from said room to said second inlet port, i. structureforming a return flow path from said rooms to said powered cooler toenable said powered cooler to cool return air from said rooms and toinclude the cooled return air in the air which said powered coolersupplies to said air-distributing passage, j. temperature responsivemeans in said rooms, k. a proportioning damper in each said air-mixingbox between the inlet ports thereof and the fan therein to vary therelative amounts of air entering each air-mixing box from saidair-distributing passage and the amounts of air entering each air-mixingbox from the room, l. continuously-open passages interconnecting saidrooms with said return air structure, m. means providing acontinuously-open path between said air-distributing passage and saidreturn air structure, n. said continuously-open passages between saidrooms and said return air structure and said continuously-open pathmeans coacting to connect said rooms with said air-distributing passagevia said return air structure, o. whereby said rooms are connected tosaid air-distributing passage both by said air-mixing boxes and by saidcontinuously-open path means and the continuously-open passages whichinterconnect said air return structure with said rooms.
 9. An atmospherecontrol system for a building having a plurality of rooms whichcomprises: a. a cooling unit that includes a blower which can supplyquantities of cooled air, b. structural elements of said building whichdefine and delimit parts of rooms of said building and which also defineand delimit part of a large cross section plenum that extends from apoint adjacent said cooling unit to the immediate proximity of saidrooms, c. the outlet of said blower of said cooling unit being connectedto said plenum for feeding cool air into said plenum from said coolingunit, and said plenum conducting said cool air to the immediateproximity of said rooms, d. a plurality of air-mixing boxes, e. saidair-mixing boxes being disposed adjacent said rooms, and each of saidair-mixing boxes having structure forming two inlet ports, a fan mountedbetween said inlet ports and a discharge port leading to a room, f. saidfan in said air-mixing box acting to move air from said inlet ports toand through said discharge port and thence into said room, g. a cool airflow path between said plenum and One of said inlet ports of each saidair-mixing box to conduct cool air from said plenum to said one inletport, h. further structural elements of said building which define anddelimit parts of rooms of said building and which also define anddelimit part of a second large cross section plenum that extends fromthe immediate proximity of said rooms to a point adjacent said coolingunit, i. the inlet of said blower of said cooling unit being connectedto said second plenum, j. a warm air flow path from each said room to asecond of said inlet ports of said air-mixing box feeding said room toconduct air from said room to said second inlet port, k. structureforming flow paths from said rooms to said second plenum to includereturn air from said rooms in the air flowing through said secondplenum, l. said second plenum conducting return air from said rooms tosaid cooling unit and thereby enabling said cooling unit to cool returnair from said rooms and to include the cooled return air in the airwhich said cooling unit supplies to the first said plenum, m.temperature responsive means in said rooms, n. proportioning dampermeans in each said air-mixing box between the inlet ports thereof andthe fan thereinto vary the relative amounts of cooled air entering eachair-mixing box from the first said plenum and the amounts of airentering each air-mixing box from the room, o. the first said plenum andsaid second plenum being horizontally-directed, p. one of said plenumsbeing located immediately above the other of said plenums, q. the lowerlimit of said one plenum and the upper limit of said other plenum beingdefined and delimited by a horizontally-directed partition means, r. thereturn air flow through said second plenum being in one directionrelative to said rooms, and s. the cold air flow through said one plenumbeing in the opposite direction relative to said rooms.
 10. Anatmosphere control system for a building having a plurality of roomswhich comprises: a. a cooling unit that includes a blower which cansupply quantities of cooled air, b. structural elements of said buildingwhich define and delimit parts of rooms of said building and which alsodefine and delimit part of a large cross section plenum that extendsfrom a point adjacent said cooling unit to the immediate proximity ofsaid rooms, c. the outlet of said blower of said cooling unit beingconnected to said plenum for feeding cool air into said plenum from saidcooling unit, and said plenum conducting said cool air to the immediateproximity of said rooms, d. a plurality of air-mixing boxes, e. saidair-mixing boxes being disposed adjacent said rooms, and each of saidair-mixing boxes having structure forming two inlet ports, a fan mountedbetween said inlet ports and a discharge port leading to a room, f. saidfan in said air-mixing box acting to move air from said inlet ports toand through said discharge port and thence into said room, g. a cool airflow path between said plenum and one of said inlet ports of each saidair-mixing box to conduct cool air from said plenum to said one inletport, h. further structural elements of said building which define anddelimit parts of rooms of said building and which also define anddelimit part of a second large cross section plenum that extends fromthe immediate proximity of said rooms to a point adjacent said coolingunit, i. the inlet of said blower of said cooling unit being connectedto said second plenum, j. a warm air flow path from each said room to asecond of said inlet ports of said air-mixing box feeding said room toconduct air from said room to said second inlet port, k. structureforming flow paths from said rooms to said second plenum to includereturn air from said rooms in the air flowing through said secondplenum, l. said second plenum conducting return air from said rooms tosaid cooling unit and thereby enabling said cooL-ing unit to cool returnair from said rooms and to include the cooled return air in the airwhich said cooling unit supplies to the first said plenum, m.temperature responsive means in said rooms, n. proportioning dampermeans in each said air-mixing box between the inlet ports thereof andthe fan therein to vary the relative amounts of cooled air entering eachair-mixing box from the first said plenum and the amounts of airentering each air-mixing box from the room, o. the first said plenumbeing located between said rooms, p. the first said structural elementsbeing the upper portions of confronting walls of said rooms plus ahorizontally-directed ceiling extending between said upper portions ofsaid confronting walls, and q. a lower ceiling defining the bottom ofthe first said plenum.